The present invention relates generally to molded articles and, more particularly, to a panel having a cover material bonded thereto and a process for producing such a panel.
To impart a decorative effect to a plastic panel or to improve the feel of the panel, a cover material, e.g., a fabric, has been bonded to plastic panels used in a variety of applications such as building materials, e.g., walls, partitions, and doors, and automotive parts, e.g., head rests, arm rests, parcel shelves, and cargo floor lid panels. For example, Japanese Patent Publication No. 4-53696 discloses a method for producing a hollow plastic article by blow molding in which a cover material such as a non-woven fabric is bonded to the exterior face of the article. In addition, Japanese Patent Application Laid-Open No. 6-134842 discloses a hollow plastic article in which reinforcing ribs are provided between the constituent walls in such a manner that defects caused by shrinkage or warping do not appear on the exterior face of one of the walls.
Hollow panels having a double-wall structure and a cover material, e.g., a fabric having outwardly protruding fuzzy hairs, bonded to the exterior face of a first wall of the panel are known. These known panels, which include reinforcing ribs formed on the interior face of a second wall having tip faces which are integrally joined to the interior face of the first wall, are formed by a method in which a parison and the cover material are first positioned between two halves of a mold and then the parison is blow molded so that the cover material is simultaneously bonded to the exterior face of the first wall of the panel. One disadvantage associated with this method, however, is that the action in which the tip faces of the reinforcing ribs are pressed against the first wall to form an integral union causes the portions of the cover material which are located above the tip faces to be pressed hard against the surface of the mold cavity. Consequently, this action impairs the appearance of the resultant panel by causing press marks to be formed on the portions of the cover material which are subjected to such hard pressing. In addition, if the cover material is a fabric having outwardly protruding fuzzy hairs, then this action causes matting of the fuzzy hairs, which also further impairs the appearance of the resultant panels. This matting phenomenon is caused by the combination of heat from the parison (which is typically at a temperature of about 200.degree. C.) and the high pressure applied against the fabric (typically about 10 atm.). Another disadvantage associated with this method is that the formation of the ribs leaves a concave indentation in the second wall at the points where the tip faces have been joined to the first wall. As a result, the exterior surface of the second wall is not a continuous flat surface.
In view of the foregoing, what is needed is a panel having a cover material bonded thereto which has an aesthetically pleasing appearance, as well as a process for producing such a panel.